CN1914768A - Small loop antenna for induction reader/writer - Google Patents
Small loop antenna for induction reader/writer Download PDFInfo
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- CN1914768A CN1914768A CNA2005800038101A CN200580003810A CN1914768A CN 1914768 A CN1914768 A CN 1914768A CN A2005800038101 A CNA2005800038101 A CN A2005800038101A CN 200580003810 A CN200580003810 A CN 200580003810A CN 1914768 A CN1914768 A CN 1914768A
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- 230000006698 induction Effects 0.000 title claims abstract description 23
- 238000004891 communication Methods 0.000 claims abstract description 34
- 238000012423 maintenance Methods 0.000 claims description 2
- 230000008054 signal transmission Effects 0.000 abstract description 3
- 238000005530 etching Methods 0.000 abstract description 2
- 230000008859 change Effects 0.000 description 39
- 239000010410 layer Substances 0.000 description 18
- 238000012546 transfer Methods 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 230000008569 process Effects 0.000 description 7
- 230000008901 benefit Effects 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 230000014509 gene expression Effects 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 229920005644 polyethylene terephthalate glycol copolymer Polymers 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000002355 dual-layer Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
- H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
- H01Q1/2216—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems used in interrogator/reader equipment
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
- H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
- H04B5/40—Near-field transmission systems, e.g. inductive or capacitive transmission systems characterised by components specially adapted for near-field transmission
- H04B5/48—Transceivers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
- H04B5/70—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes
- H04B5/77—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes for interrogation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
- H04B5/70—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes
- H04B5/79—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes for data transfer in combination with power transfer
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Near-Field Transmission Systems (AREA)
- Details Of Aerials (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
Abstract
There is provided a small antenna for induction reader/writer capable of increasing the communication distance even when the antenna area or power supply to the antenna is restricted. The small antenna for induction reader/writer has a two-layer structure of loop antennas arranged at a predetermined interval and each comprising a printed board(2) for forming a loop pattern(1), the loop pattern(1) formed by etching the printed board(2), and a start terminal(3) and an end terminal(4) for supplying signal transmission power and outputting a received signal.
Description
Technical field
The present invention relates to a kind of loop aerial of compactness.
Background technology
Loop aerial is often used as basic antenna.Looped antenna configuration is simple, manufactures compactly easily and configuration at low cost, therefore is used to conventional induction type read/write device.
In recent years, induction type read/write device (for example, non-contact type card) comes into operation, for example according to the ISO standard, that is, and the non-contact type card of ISO14443, ISO15693 etc.In the middle of them,, adopt the communication system that meets ISO14443 under many circumstances as the non-contact type card that in reaching the communication range of 10cm, carries out work.Simultaneously, the ISO15693 standard provides the communication range that reaches about 70cm, therefore many equipment utilizations it as RF-ID (radio-frequency (RF) identification).When on the induction type read/write device, loop aerial being installed, normally being used for that by use the spiral pattern with multiturn spiral is carried out etched printed circuit board (PCB) and forming loop aerial.
For example, Figure 1A and 1B show the example of the conventional structure of loop aerial.
Figure 1A shows the loop aerial, the circular pattern 29 that passes through formation such as etch process on this printed circuit board (PCB) 30 that comprise the printed circuit board (PCB) 30 that is formed with circular pattern 29 on it, be used to provide and be used to send the starting point terminal 31 of the electric power of signal and the signal that output is received and the vertical view of terminal point terminal 32.
Incidentally, the example structure shown in Figure 1A shows in formation and has circular pattern 29 under the situation of ring of two circle spirals.
Figure 1B shows the cross section of the loop aerial shown in Figure 1A.Shown in Figure 1B, conventional loop aerial is made of a plurality of rings of different size, to form the helical annular pattern on a plate.
[patent documentation 1] Japanese Patent Application Laid-Open communique No.54-008441
[patent documentation 2] Japanese Patent Application Laid-Open communique No.11-272826
In the spiral loop that constitutes by a plurality of spirals of loop aerial shown in Figure 1A and 1B, antenna area (promptly, area by magnetic linkage in the ring that the circular pattern by loop aerial forms) and the electric power that can offer antenna in fact be subjected to the restriction of design constraint, the size of the transmitter or the receiver of this loop aerial for example is installed, perhaps battery capacity on it.Antenna area that is allowed and the electric power that provided etc. are feasible to be difficult to increase field intensity on the direction perpendicular to antenna surface, therefore be difficult to increase read/write distance (that is communication range).
Here, can expect coming the etching circular pattern by on by the single plate in the antenna shown in Figure 1A and the 1B, the spiral number of turn further being increased to four or five, but field intensity only increases on the direction parallel with antenna surface, (do not note and do not increase in vertical direction, this meets screw law, and produces along dextrorotary direction with respect to the sense of current that flows in pattern.If a plurality of patterns that exist along continuous straight runs to arrange, then therefore this field does not increase in vertical direction).Increase transmitting power to strengthen the method for radio wave although exist, it is big that the size of power subsystem becomes, and produces more heats and increased cost.This is a problem.
However, recently more and more need to come the technology of expanding communication scope by little antenna area and low-power.
Summary of the invention
Consider aforesaid problem, challenge of the present invention provides a kind of compact loop aerial that uses in the induction type read/write device, even antenna area or the power supply of antenna is restricted, this compactness loop aerial also can the expanding communication scope.
The described invention of the claim 1 here is the loop aerial that uses in the induction type read/write device, it is characterized in that, by making circular pattern keep preset distance mutually, come stacked two or more circular patterns, each circular pattern is by at least one circle spiralization, interconnect each starting point of all stacked circular patterns and its each terminal point that interconnects, all stacked circular patterns thus are connected in parallel.
Invention according to claim 1, interconnection each starting point and its each terminal point that interconnects of stacked circular pattern, all stacked circular patterns thus are connected in parallel, and the electric current in all patterns is flowed along identical direction, on identical direction, to produce each magnetic field for all circular patterns, cause overlapping magnetic field, thereby increase magnetic field intensity, realize the effect of expanding communication scope thus.
Stacked circular pattern is constructed to be connected in parallel with transmitting element, and this transmitting element sends signal by loop aerial, therefore realizes increasing the benefit that offers the electric power of loop aerial from transmitting element minimumly.
The described invention of the claim 2 here is the loop aerial that uses in the induction type read/write device according to claim 1, it is characterized in that, mode with multilayer is provided with two or more plates, each plate all is formed with a circular pattern on single plate, described plate keeps preset distance mutually.
Invention according to claim 2 has obtained and the identical effect of the described invention of claim 1.Promptly, by each starting point of the stacked circular pattern that interconnects and its each terminal point that interconnects, all stacked circular patterns thus are connected in parallel, and the electric current in all patterns is flowed along identical direction, on same direction, to produce each magnetic field for all circular patterns, cause overlapping magnetic field, thereby increase magnetic field intensity, realize the effect of expanding communication scope thus.
The circular pattern that forms on stacked plate is constructed to be connected in parallel with transmitting element, and this transmitting element sends signal by loop aerial, therefore realizes increasing the benefit that offers the electric power of loop aerial from transmitting element minimumly.
The described invention of the claim 3 here is the loop aerial that uses in the induction type read/write device according to claim 1, it is characterized in that, by mutual maintenance preset distance, in the mode of multilayer circular pattern is arranged on the single plate.
Invention according to claim 3 has obtained and the identical effect of the described invention of claim 1.Promptly, by each starting point of the stacked circular pattern that interconnects and its each terminal point that interconnects, all stacked circular patterns thus are connected in parallel, and the electric current in all patterns is flowed along identical direction, on same direction, to produce each magnetic field for all circular patterns, cause overlapping magnetic field, thereby increase magnetic field intensity, realize the effect of expanding communication scope thus.
The circular pattern that forms on stacked plate is constructed to be connected in parallel with transmitting element, and this transmitting element sends signal by loop aerial, has therefore realized increasing the benefit that offers the electric power of loop aerial from transmitting element minimumly.
The described invention of the claim 4 here is according to claim 1,2 or 3 the loop aerial that uses in the induction type read/write device, it is characterized in that, also comprise: connect converting unit between starting point, be used between each starting point of stacked circular pattern, optionally connecting; And connect converting unit between terminal point, be used between each terminal point of stacked circular pattern, optionally connecting.
Invention according to claim 4, except the effect identical with the described invention of claim 1, the structure that is used for connecting converting unit between the terminal point that connects converting unit between the starting point that optionally connects between each starting point of stacked circular pattern and be used for optionally connecting between each terminal point at stacked circular pattern has also been realized making it possible to adjust and the benefit that is used for sending by loop aerial the quantity of the circular pattern that the transmitting element of signal is connected in parallel.
The described invention of the claim 5 here is the loop aerial that uses in the induction type read/write device according to claim 4, it is characterized in that, is connected converting unit according to connecting between the communication range switching start point between converting unit and terminal point.
Except the effect identical with the described invention of claim 1 to 4, invention according to claim 5 can also be connected between converting unit and terminal point that converting unit reduces and the quantity of the circular pattern that transmitting element is connected in parallel by connecting between starting point, be provided for the antenna of short communication range, and is connected between converting unit and terminal point by connecting between starting point that converting unit increases and the quantity of the circular pattern that transmitting element is connected in parallel, be provided for the antenna of long communication range.
Description of drawings
Figure 1A shows the vertical view of the example of conventional loop aerial;
Figure 1B shows the profile of the example of conventional loop aerial;
Fig. 2 A shows the vertical view according to the structure of the loop aerial of first embodiment of the invention;
Fig. 2 B shows the profile according to the structure of the loop aerial of first embodiment of the invention;
Fig. 3 shows the magnetic field intensity according to the loop aerial of first embodiment of the invention;
Fig. 4 shows the structure according to the loop aerial of second embodiment of the invention; And
Fig. 5 illustration according to the loop aerial switched system of second embodiment of the invention.
Embodiment
Below be to the description of Fig. 5 with reference to Fig. 2 A to the preferred embodiments of the present invention.
Fig. 2 A and 2B show the structure according to the loop aerial of first embodiment of the invention.
Fig. 2 A shows the vertical view according to the structure of the loop aerial of first embodiment of the invention.
The compact loop aerial that uses in the induction type read/write device according to present embodiment is by making the ground floor loop aerial and second loop aerial (not shown among Fig. 2 A) keep preset distance mutually and the compact loop aerial of the stacked ground floor loop aerial and second loop aerial, this first loop aerial comprises: first printed circuit board (PCB) 2, be formed with first circular pattern 1 on it, this first circular pattern 1 is formed on first printed circuit board (PCB) 2 by etch process etc.; And starting point terminal 3 and terminal point terminal 4, be used to provide the electric power that is used for the signal transmission and export the signal that is received, this second layer loop aerial comprises second printed circuit board (PCB) 6, be formed with second circular pattern 5 on it, this second circular pattern 5 is formed on second printed circuit board (PCB) 6 by etch process etc.; And starting point terminal and terminal point terminal, be used to provide the electric power that is used for the signal transmission and export the signal that is received.
Fig. 2 B shows the profile according to the structure of the loop aerial of first embodiment of the invention.
Be formed on the starting point terminal 3 and starting point terminal (not shown) interconnection that is formed on the circular pattern 5 on second printed circuit board (PCB) 6 of the circular pattern 1 on first printed circuit board (PCB) 2 here, equally, the terminal point terminal 4 that is formed on the circular pattern 1 on first printed circuit board (PCB) 2 also interconnects with the terminal point terminal (not shown here) that is formed on the circular pattern 5 on second printed circuit board (PCB) 6, and provide electric power, so that the sense of current that flows in first circular pattern 1 is identical with mobile sense of current in second circular pattern 5.
By this structure, first circular pattern 1 and second circular pattern 5 be used for providing the power subsystem (not shown) of electric power to be connected in parallel here to this loop aerial, make the increase that the electric power that provided can be provided thus, this power subsystem is connected with the terminal point terminal with above-mentioned starting point terminal.
By keeping preset distance 7, first printed circuit board (PCB) 2 and second printed circuit board (PCB) 6 that will have the circular pattern with two circle spirals 1 by formation such as etch processs are stacked, set up this preset distance 7 by adjusting, with the maximum magnetic field strength that obtains entire antenna (that is, perpendicular to the magnetic field intensity on the direction of antenna surface).According to present embodiment, for the area of the foursquare antenna that is constructed to about 10cm (length) * about 10cm (wide), this preset distance 7 is about 2mm.
Although when the distance 7 between first printed circuit board (PCB) 2 and second printed circuit board (PCB) 6 being set to zero (0), look that the magnetic field intensity of entire antenna becomes maximum, but since such as be formed on first circular pattern 1 on first printed circuit board (PCB) 2 intrinsic self-induction, be formed on second circular pattern 5 on second printed circuit board (PCB) 6 intrinsic self-induction and the influence of the mutual inductance between first circular pattern 1 and second circular pattern 5, the actual range that magnetic field intensity becomes maximum is considered to variable.
For example, when the magnetic flux phi that is produced by the electric current I that flows in first circular pattern 1 is passed second circular pattern 5, owing to first circular pattern 1 that influenced by second circular pattern 5 and the mutual inductance between second circular pattern 5, and produce back electromotive force in second circular pattern 5, thereby the electric current I that flows therein reduces.Therefore, because mobile therein electric current I, the magnetic field intensity that produces in second circular pattern 5 reduces.In addition, passing the magnetic linkage of the annular that is formed by second circular pattern 5 and the distance between first circular pattern 1 and second circular pattern 5 increases inversely.Therefore, simply by the distance 7 between first printed circuit board (PCB) 2 and second printed circuit board (PCB) 6 being set to zero (0), can not make the magnetic field intensity maximization of entire antenna.
As like that can the expanding communication scope in the structure shown in Fig. 2 A and the 2B,, therefore can provide the benefit of expansion reading/writing distance for the induction type read/write device even the area of antenna is limited with the stacked loop aerial of the form of multilayer.
Although present embodiment has been described the compact loop aerial that uses under the situation of stacked two stacked loops shown in Fig. 2 A and 2B in the induction type read/write device, the present invention is not limited to stacked two stacked loops.That is, it can be constructed to have two-layer or more multi-layered loop aerial, rather than two-layer by shown in the embodiment, can further expand communication range thus.
In addition, first circular pattern 1 shown in Fig. 2 A and the 2B and second circular pattern 5 are used for the situation of two circles, but the invention is not restricted to this.Can adopt the annular of multiturn, that is, and a circle or multiturn more.
Simultaneously, the plate here uses the printed circuit board of inflexibility, the thin web that forms but it can use by the copper circuit pattern being applied to flexible base film (for example, PET (PETG) film) goes up.
Fig. 3 shows the magnetic field intensity according to the loop aerial of first embodiment of the invention.
Fig. 3 shows as the magnetic field intensity to the function of the distance of antenna surface, has represented a characteristic curve, and wherein trunnion axis represents that (unit: mm), vertical axis is represented magnetic field intensity (unit: A/m) for the distance of antenna surface.
With reference to Fig. 3, solid line 8 expressions are by the characteristic of Figure 1A and the illustrative conventional loop aerial of 1B, and dotted line 9 expressions are according to the antenna characteristics of present embodiment.The solid line that is parallel to the horizontal line drafting of the distance of representing to antenna surface (mm) represents to allow to read by communication the minimum value (that is, reading lower limit) of the magnetic field intensity of signal.If being lower than this, magnetic field intensity reads lower limit, then can not read signal by communication because a power (fieldpower) is not enough, therefore magnetic field intensity greater than in the scope that reads lower limit (that is, more than reading the line of lower limit) in the distance of antenna surface, can carry out signal and read.
Should be appreciated that according to the use of the antenna of present embodiment communication range has been expanded distance shown in Figure 3 (1).
Fig. 4 shows the structure according to the loop aerial of second embodiment of the invention.
The compact loop aerial that uses in the induction type read/write device according to present embodiment comprises at least: form the ground floor loop aerial 12 that circular pattern 11 thereon constitutes by first printed circuit board (PCB) 10 with by etch process etc.; Form the second layer loop aerial 15 that circular pattern 14 thereon constitutes by second printed circuit board (PCB) 13 with by etch process etc. with circular pattern; Form the shellring shape antenna 18 that circular pattern 17 thereon constitutes by the 3rd printed circuit board (PCB) 16 with by etch process etc.; Be connected to the starting point terminal 19 and the terminal point terminal 20 of ground floor loop aerial 12, the starting point terminal 21 that is connected to second layer loop aerial 15 and terminal point terminal 22 and be connected to the starting point terminal 23 of shellring shape antenna 18 and first change over switch 25 of terminal point terminal 24; And be connected to the starting point terminal 21 and the terminal point terminal 22 of second layer loop aerial 15 and be connected to the starting point terminal 23 of shellring shape antenna 18 and second change over switch 26 of terminal point terminal 24.
By between layer, keeping predetermined space, come stacked ground floor loop aerial 12, second layer loop aerial 15 and shellring shape antenna 18, this is adjusted at interval and makes the magnetic field intensity (that is, perpendicular to the magnetic field intensity on the direction of antenna surface) of entire antenna maximize.
The TCU transfer control unit 28 that is equipped with in transmission of not describing in the accompanying drawing of present embodiment is shown or the receiving element is controlled each change over switch by being connected to each change over switch, to control first change over switch 25 and second change over switch 26.
Here, in the present embodiment, TCU transfer control unit 28 has the function that each change over switch of indication is changed according to communication range, and cut comprise be provided in send or receiving element in CPU (CPU), (for example be used for storage data, be used to make CPU carry out the program of conversion and control) nonvolatile memory (for example, EEPROM), (for example be used for the register of operation of CPU or nonvolatile memory, RAM), these elements can be made of logical circuit (for example, transistor).
First change over switch 25 and second change over switch 26 are made of transistor etc., and the state of each change over switch is switched on according to the control signal from TCU transfer control unit 28 or ends.
The starting point of each stacked loop and terminal point are connected to power amplifier 27, and this power amplifier 27 is provided in transmission or the receiving element, is not illustrated in the accompanying drawings, and it is used for powering to antenna by first change over switch 25 and second change over switch 26.
When first change over switch 25 is in cut-off state (correspondingly, second change over switch 26 also is in cut-off state) time, loop aerial according to present embodiment becomes the antenna (that is, second layer loop aerial 15 and shellring shape antenna 18 are isolated in the mode of circuit with transmission and receiving element) that only is made of ground floor loop aerial 12.
When first change over switch 25 is in conducting state and second change over switch 26 and is in cut-off state, antenna becomes the antenna that constitutes by stacked ground floor loop aerial 12 and second layer loop aerial 15, and distance between the two remains predetermined space (that is, shellring shape antenna 18 is isolated in the mode of circuit with transmission and receiving element).
In addition, when both are in conducting state simultaneously when first change over switch 25 and second change over switch 26, this antenna becomes the antenna that constitutes by stacked ground floor loop aerial 12, second layer loop aerial 15 and shellring shape antenna 18, and distance to each other remains predetermined space.
Fig. 5 illustration according to the loop aerial switched system of second embodiment of the invention.
Fig. 5 illustration have under the situation of relation of A＜B＜C at communication range A, B and C, be used between one to three layer, changing the table of the structure of loop aerial as the result that 28 pairs first change over switches 25 of TCU transfer control unit shown in Figure 4 and second change over switch 26 are controlled.Table shown in Figure 5 is for example by the included ROM pre-stored of TCU transfer control unit 28, and controls with reference to its clauses and subclauses one by one by CPU.
When transducer (not shown at this) notice CPU communication range is " C ", CPU transmits control signal to first change over switch 25 with reference to by above-mentioned table address stored, indicates it to adopt conducting state, and transmit control signal to second change over switch 26, indicate it to take conducting state.First change over switch 25 and second change over switch 26 are according to taking conducting state from the control signal of TCU transfer control unit 28, to constitute three layers of antenna, obtain communication range thus according to the maximum in the middle of the structure of present embodiment by stacked ground floor loop aerial 12, second layer loop aerial 15 and shellring shape antenna 18.
Equally, when transducer (not shown at this) notice CPU communication range is " B ", the CPU reference is by above-mentioned table address stored, transmit control signal to first change over switch 25, indicate it to take conducting state, and transmit control signal to second change over switch 26, indicate it to take cut-off state.According to the control signal from TCU transfer control unit 28, first change over switch 25 is taked conducting state, and second change over switch 26 is taked cut-off state, to constitute dual-layer atenna by stacked ground floor loop aerial 12 and second layer loop aerial 15.
In addition, when transducer (not shown at this) notice CPU communication range was " A ", CPU transmitted control signal to first change over switch 25 and second change over switch 26 with reference to by above-mentioned table address stored, indicates it to take cut-off state.According to control signal from TCU transfer control unit 28, first change over switch 25 and second change over switch 26 are taked cut-off state, to constitute the antenna that only constitutes, obtain communication range thus according to the minimum in the middle of the structure of present embodiment by ground floor loop aerial 12.
As mentioned above, the ability that changes communication range as required makes and can further suppress power consumption.Can prevent easily that also radio wave is launched too far, and influence other equipment.
Notice that in the superincumbent description, first change over switch 25 is in conducting state with second change over switch 26 and means that they are connected in the mode of circuit, mean that they disconnect in the mode of circuit and be in cut-off state.
Above description at TCU transfer control unit 28 according to the communication range situation of the stacked state of converting antenna automatically, but it is not limited to the stacked state of converting antenna automatically.For example, can be provided with first change over switch 25 and second change over switch 26, manually change by using DIP switch (dip switch) etc.
In addition, initial condition during the communication beginning can be constructed to shellring shape antenna, and first change over switch 25 and second change over switch 26 can be controlled as according to communications status or communication range and transformational structure, with the structure of conversion loop aerial between to three layer.
According to the present invention the loop aerial illustration of first and second embodiment situation that on each plate, forms a circular pattern and come constructing antennas by stacked these plates, but the invention is not restricted to this.For example, can construct loop aerial by keeping predetermined space stacked two or more circular patterns on single plate.In this case, for example come stacked each circular pattern by the insulator layer in the middle of being positioned at, the thickness of this insulator layer is adjusted to and makes magnetic field intensity (that is, perpendicular to the magnetic field intensity on the direction of the antenna surface) maximization of entire antenna.
Alternatively, can construct loop aerial by on the end face of single plate and bottom surface, forming circular pattern.In this case, the thickness of plate can be adjusted to and make magnetic field intensity (that is, perpendicular to the magnetic field intensity on the direction of the antenna surface) maximization of entire antenna.
According to the first and second aspects of the present invention, it is identical requiring the shape and size (for example, the size of full annular, the thickness and the width that constitute this annular conductive pattern, or the like) of the circular pattern of looping antenna, but the invention is not restricted to this.If shape and size are different to a certain extent, it also is in the scope of the present invention, even and the area of antenna and suffer restraints to the electric power that it provides, also can obtain the benefit of expanding communication scope.
As mentioned above, each aspect of the present invention all makes and can be provided in the compact antenna that uses in the induction type read/write device, though antenna area or limited to the power supply of antenna, also can the expanding communication scope.
Claims (5)
1, a kind of loop aerial that in the induction type read/write device, uses, it comprises:
Two or more circular patterns, these circular patterns keep preset distance mutually, and each circular pattern is all by at least one circle spiralization, wherein:
Interconnect each starting point of all stacked circular patterns and its each terminal point that interconnects, all stacked circular patterns thus are connected in parallel.
2, the loop aerial that in the induction type read/write device, uses according to claim 1, wherein:
Mode with the multilayer of mutual maintenance preset distance is provided with two or more plates, and each plate all is formed with a described circular pattern.
3, the loop aerial that in the induction type read/write device, uses according to claim 1, wherein:
Mode with multilayer on single plate is provided with described circular pattern, and above-mentioned circular pattern keeps preset distance mutually.
4, according to claim 1, the 2 or 3 described loop aerials that in the induction type read/write device, use, also comprise:
Connect converting unit between starting point, be used between each starting point of described stacked circular pattern, optionally connecting, and
Connect converting unit between terminal point, be used between each terminal point of described stacked circular pattern, optionally connecting.
5, the loop aerial that in the induction type read/write device, uses according to claim 4, wherein:
Connect between described starting point and be connected converting unit between converting unit and described terminal point and according to communication range connection changed respectively.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004025358A JP2005218021A (en) | 2004-02-02 | 2004-02-02 | Small loop antenna for inductive reader/writer |
| JP025358/2004 | 2004-02-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1914768A true CN1914768A (en) | 2007-02-14 |
Family
ID=34823979
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2005800038101A Pending CN1914768A (en) | 2004-02-02 | 2005-01-14 | Small loop antenna for induction reader/writer |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US7259726B2 (en) |
| EP (1) | EP1713145A4 (en) |
| JP (1) | JP2005218021A (en) |
| KR (1) | KR100842141B1 (en) |
| CN (1) | CN1914768A (en) |
| WO (1) | WO2005074072A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103457040A (en) * | 2012-05-31 | 2013-12-18 | Nxp股份有限公司 | Ajustable antenna |
| CN104025471B (en) * | 2011-11-17 | 2017-07-04 | 维拓警报通信公司 | VLF transmitting antennas system, method and apparatus |
| CN111164901A (en) * | 2017-10-03 | 2020-05-15 | 法国大陆汽车公司 | Near field communication device |
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| JP3737606B2 (en) * | 1997-06-30 | 2006-01-18 | 株式会社日立国際電気 | Planar antenna |
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| JP2001325574A (en) * | 2000-05-17 | 2001-11-22 | Denso Corp | Ic card |
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-
2004
- 2004-02-02 JP JP2004025358A patent/JP2005218021A/en active Pending
-
2005
- 2005-01-14 WO PCT/JP2005/000413 patent/WO2005074072A1/en active Application Filing
- 2005-01-14 CN CNA2005800038101A patent/CN1914768A/en active Pending
- 2005-01-14 EP EP05703652A patent/EP1713145A4/en not_active Withdrawn
- 2005-01-14 KR KR1020067017418A patent/KR100842141B1/en not_active IP Right Cessation
-
2006
- 2006-07-31 US US11/496,283 patent/US7259726B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104025471B (en) * | 2011-11-17 | 2017-07-04 | 维拓警报通信公司 | VLF transmitting antennas system, method and apparatus |
| CN103457040A (en) * | 2012-05-31 | 2013-12-18 | Nxp股份有限公司 | Ajustable antenna |
| US9819402B2 (en) | 2012-05-31 | 2017-11-14 | Nxp B.V. | Ajustable antenna |
| CN111164901A (en) * | 2017-10-03 | 2020-05-15 | 法国大陆汽车公司 | Near field communication device |
| CN111164901B (en) * | 2017-10-03 | 2022-01-18 | 法国大陆汽车公司 | Near field communication device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2005218021A (en) | 2005-08-11 |
| WO2005074072A1 (en) | 2005-08-11 |
| KR20060114373A (en) | 2006-11-06 |
| EP1713145A1 (en) | 2006-10-18 |
| US20070030207A1 (en) | 2007-02-08 |
| US7259726B2 (en) | 2007-08-21 |
| KR100842141B1 (en) | 2008-06-27 |
| EP1713145A4 (en) | 2008-12-10 |
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